Time Series Analysis Of Catch Effort Series Gulf Of Mexico Shrimp Fisheries

Author : James M. Nance
Publisher :
ISBN 13 :
Total Pages : 37 pages
Book Rating : 4.:/5 (523 download)

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Download or read book Effort Trends for the Gulf of Mexico Shrimp Fishery written by James M. Nance and published by . This book was released on 1993* with total page 37 pages. Available in PDF, EPUB and Kindle. Book excerpt: This report provides a description of the data and data collection procedures used to collect statistics from the shrimp fisheries in the Gulf of Mexico and discusses recent trends in fishing effort. By providing these descriptions, it is intended that those who use the data will have a better understanding of the shrimp databases and can assist in efforts to improve the estimates. Each of the indicators of effort mentioned above generally show the same trends with regards to overall effort in the nearshore and offshore shrimp fishery in the Gulf of Mexico. Days fished (actual period of time with trawls in the water) is the indicator of shrimp effort most closely related to F, since it depicts pressure on the stocks. This effort value peaked in 1987, dropped in 1988, but has shown a slight increase each of the past three years. This overall increase has not occurred everywhere, but the decreases in some areas are simply less than the increases experienced in other areas. The interviewed CPUE values, with their overall decreasing trend, lend support to the estimated days fished value. The total number of nearshore and offshore trips peaked in 1987, dropped in 1988, and has remained near or slightly below that same level of the past several years. Although the trips have remained at nearly the same level, the average interviewed value of days fishing per trip has shown an increase. This increase has not occurred at all ports, but most show the increased trend. This increase in days fishing per trip, with the nearly stable level in total number of trips also lends support to the estimated days fished value. There is no indication, that even with the decrease in total number of interviews, that a different type of vessel is being interviewed presently than was interviewed in the early 1980's. Average length of interviewed vessels have not shown any major shifts (i.e., different sized vessels being interviewed in 1981 than in 1992). Even number of vessels in the fishery, which is the least complex method to calculate effort, shows number have dropped in the VOUF, but have remained more stable in the landings file.